1. Field of the Invention
The present invention relates to a display device which mounts self light emitting elements such as EL (electroluminescence) elements, organic EL elements, or other self-luminous display elements thereon.
2. Description of the Related Art
A self light emitting element represented by an EL (electroluminescence) element, an organic EL element or the like has a property that the light-emission brightness is proportional to a quantity of electric current which flows in the self light emitting element and hence, a gray-scale display can be realized by controlling the quantity of electric current which flows in the self light emitting element. A display device can be manufactured by arranging a plurality of such self light emitting elements.
However, the self light emitting element has the characteristic that when the self light emitting element is used for a long time, the degradation of the self light emitting element progresses with time thus lowering the light-emission brightness thereof, wherein the degree of degradation depends on the duration of light emission. Accordingly, a burn-in-like pattern is generated corresponding to a light emission state (display pattern) of an individual pixel.
JP-A-2004-287345 discloses a technique which measures the light emission characteristic of an organic EL element which constitutes a self light emitting element and corrects display data based on the measured light emission characteristic. Here, the measured light emission characteristic is a quantity of electric current which flows in the self light emitting element, and a value of the measured current quantity is stored in a memory capacitance after A/D conversion. By adding a correction quantity corresponding to the stored current quantity to the display data, the irregularities of the light emission characteristic is corrected. In this manner, to ensure the stable light emission brightness among pixels of an organic EL display panel, a measurement result acquired by the current measurement is subject to the A/D conversion, and the acquired digital data is fed back to a drive signal for a light emitting element.
Although JP-A-2004-287345 discloses the detection of the current quantity at the time of display, this patent document does not take into consideration a detection time, the appearance attributed to a display state at the time of detection and the operability. Further, at the time of detection, a specific display, for example, a white display is performed, and when the detection time is prolonged, it is expected that a user is forced to continuously observe the display.